Electronic watch



Nov. 8, 1966 M. HETZEL ETAL 3,233,495

ELECTRONIC WATCH Filed Feb. 16, 1965 5 Sheets-Sheet 1 Nov. 8, 1966 M.HETZEL ETAL 3,283,495

ELECTRONIC WATCH Filed Feb. 16, 1965 5 Sheets-Sheet 2 ELECTRONIC WATCH 5Sheets-Sheet 5 Filed Feb. 16. 1965 United States Patent 3,283,495ELECTRONIC WATCH Max Hetzel, Bienne, and Rmy Seigneur, Tavannes,Switzerland, assignors to Centre Electronique Horloger S.A.,

Neuchatel, Switzerland Filed Feb. 16, 1965, Ser. No. 433,033 Claimspriority, application Switzerland, Feb. 18, 1964, f 1,966/64; Jan. 6,1965, 125/65 6 Claims. (Cl. 58-23) 1 The present'invention relates to:an electronic watch comprising .a deflection oscillator serving both asa timebasis and as a driving member.

, Inthe watches of that type, the mechanical oscillator has in generalthe shape of 1a tuning-fork located in the central portion of the case.Such an arrangement has various drawbacks, since the space defined bythe case is thus divided into two parts, which makes it difficult tomount the gear-train for driving the hands and the date disc, and insome cases other indicator devices. Again, the room available for thebattery is very limited, so that under certain circumstances it isnecessary to resort to several batteries or to a special battery thecross-section of which is not circular.

In addition, with the usual tuning-forks, one runs the risk that thewhole device be urged by forces beyond its yield strength, all thedeformation energy being dissipated in a relatively small space in thevicinity of the tuningfork foot.

The object of the present invention is to provide a resonator which isdevoid of the above-mentioned drawbacks. The object of the presentinvention is also to provide a resonator, the shape of which is suchthat it follows the periphery of the watch case through the majorportion of its length.

The features of the present invention will be disclosed hereafter,reference being had to the accompanying drawing in which FIG. 1 is aplan view of a clockwork movement according to the invention, 1

FIG. -2 is a cross-section of FIG. 1 along IIII,

FIG. 3 is a cross-section of FIG. 1 along III-III,

FIG. 4 is .a partial cross-section of FIG. 1 along IVIV,

FIG. 5 is the diagram of the electric circuit of that watch, p FIG. 6 is"a plan view of a second form of embodiment of the watch according tothe invention, showing only the resonator in its case, and

FIG. 7 is a cross-section of FIG. '6 along VII-VII.

FIGS. 1 and 2 show a bottomeplate 1 to which is fixed, by means ofthreescrews 2, the V-shaped foot 3a of an 'audio frequency resonator 3. Theoscillating parts of that resonator have approximately the shape of asmall Omega, and they are connected to the foot 3a by :a link 3b. ,Th-eoscillating parts are essentially constituted by two oscillating arms 30and 3d which, through the major portion oftheir length, run along theperiphery 1a of the bottom plate 1 which is at the same time theperiphery of the clockwork movement. As can be seen in FIG. 2, there isprovided between arms 30, 3d, on the one hand, and bottom plate 1, .onthe other hand, a certain space, in order that the arms can oscillatefreely.

. At the extremity of each of the arms 3c and 3d is welded a magnetic.head, respectively 14 and 115.

FIG. 3 shows that the magnetic head 14, which is in mirror-symmetry withthe magnetic head 15, is constituted by -a soft iron part 4, thecross-section of which is in the shape of a U, and by polar pieces 5aand 5b fixed to the arms 4a and 4b of the U shaped iron 4, the shape ofwhich 3,283,495 Patented Nov. 8, 1966 corresponds to that of the coil.Whereas the resonator proper 3 is preferably made of a material with alow thermo-elas-tic coefiicient, such as for instance an [alloy going bythe name of Elinvar, Nivarox, Ni-span-C, or Thermelas-t, one can use forpart 4, instead of soft iron, a material such as Per-mendur. Elinvar isan alloy composed of 36% nickel, 12% chromium, 4% tungsten, at most 0.1%carbon and at most 2% manganese, balance iron. Nivarox consists of35-40% nickel, 1% beryllium, 0. 1% carbon, traces of magnesium, siliconand titanium, the balance iron. Ni-span-C and Thermelast consist of3540% nickel, traces of other elements, residue iron. Per-mendurconsists of 50% iron, 50% columbium, or 49% iron, 49% columbiu-m and 2%vanadium. Polar pieces 5a and 5b are made of a material with a highcoercitive field, such as an alloy containing platinum and cobalt. Themagnetic field in the air gap between polar pieces 5a and 5b isessentially homogenous, and the lines of force are at right angles tothe plane of the bottom-plate 1 and, therefore, to the plane in which islocated the resonator 3 and in which its arms 30 and 3d oscillate.

On each of the magnetic heads 14 and 15 is placed, by means of a screw6, la finger which is friction-tight fitted, with its axis of rotationat right angles to the oscillation plane and its centre of gravity notcoincident with its axis of rotation, so that when the finger isrotated, its centre of gravity and, therefore, the centre of gravity ofthe whole oscillating arm, is shifted and the natural frequency of thatarm is modified. Each of the magnetic heads 14 and 15 carries scalerespectively 14a and 15a, on which can be read the frequency changes inseconds per day. Fingers 7 are preferably constituted by a small pointedmetal tongue, squeezed under the head of the corresponding screw 6. Inorder to prevent the resonator from being damaged by shocks, anamplitude limitator 47 is .fixed in the bottom plate 1 in the vicinityof each of the magnetic heads, with a view to restricting theoscillation amplitude of said magnetic heads in the direction oppositeto the bottom-plate and towards the periphery of s the latter.

FIG. 5 is a diagram of the electric circuit for maintainingoscillations. This circuit comprises the pick-up coil 9, the energizingcoil 10, the capacitor 11, the resistor 12, the transistor 13 and thebattery 8. The base- I electrode 13b of transistor 13 is connectedthrough resisplate is either the positive pole or the negative pole, ac-

cording to the transistor used.

As can be seen in FIGS. 2 and 3, thetwo coils 9 and 10 are fiat ellipticcoils, and they are removably mounted on a rib 16a of a case 16 ofplastic material. In said elliptic :case are also mounted the capacitor11, resistor 12 and transistor 13, whereas the two coils 9 and 10 are sodimensioned as to intersect all the lines of force of the magnetic fieldappearing in the air-gap of magnetic heads 14 and 15. Battery 8 rests byits negative pole 8 on bottom-plate 1; it is housed in a cylindricalrecess 1b of bottom plate 1, and kept in that position by a spring 17fixed in turn by a screw 18 which is electrically insulated frombottomplate 1. Between spring 17 and the cover of battery 8, which atthe same time constitutes its positive pole 8b, the-re is gripped anelectric conductor 19 in metal socket a and connected to resistor 12,on-the one hand, and to the collector-electrode 130 of transistor 13, onthe other hand. In FIG. 1 can be seen the conductor 21 which connectscapacitor 11 to pick-up coil 9 and also the conductor 22 which connectsthe emitterelectrode 13a of transistor 13 to the junction point of coils9 and 10.

That circuit operates as follows:

Whenever one of the arms of resonator 3 is shifted under the action ofan accidental movement, a voltage is induced in pick-up coil 9, whichresults in the production of a current in the energisin-g coil 10, saidcurrent giving rise to a magnetic field which drives magnetic heads 14and 15 in the direction of the original displacement. As soon as theamplitude defined by the resiliency of resonator 3 is reached, the armsoscillate in the opposite direction. After a few to-andtrom movements,the oscillation is stabilised and arms 30 and 3d oscillate at a constantfrequency and with a constant amplitude, so that magnetic heads 14 and15 periodically draw near to, and withdraw from, each other.

The adjustment of the desired frequency can be obtained in the course ofmanufacturing, by slightly stripping the oscillating arms at some placeor other: the areshaped segments 32 and 3 of arms 30 and 3d can be madethinner, for instance by means of a drill.

The conversion of the movement of translation of the arms to a rotarymovement is achieved by means of a pawl fixed to one of the arm-s (inthe present instance, arm 311), said pawl driving a ratchet-wheel 23.The teeth of said ratchet-wheel are so dimensioned that wheel 23 rotatesby one tooth for every oscillation of the resonator. The backwardrotation of wheel 23 is impeded by a blocking pawl 25 fixed tobottom-plate 1. To the staff of ratchet wheel 23 is fixed a pinion 23ain mesh with .a toothed wheel 26, the pinion 26a of which meshes in turnwith wheel 27. None of the spindles of these wheels is shown in thefigures, in order to render these wheels more visible. Wheel 27 drives,through the medium of a wheel 28, the seconds-wheel 29, to the staff 30of which is tfiXCd the seconds-hand 31, as can be seen in FIG. 4. Pinion28a is integral with wheel 28, and meshes with a wheel 32, the pinion32a of which meshes in turn with a wheel 33. Pinion 33a integral withthat wheel meshes with the minutes-wheel 34, fixed to a cannon-pinion 35oo-axial with the seconds staff '30 and carrying the minutes-hand 36,and also a pinion 34a driving an intermediate wheel 37, the pinion 37dof which inesheswith the hour wheel 38. The latter is fixed to thecannon-pinion 39 carrying the hour hand 40. The movement of theoscillator 3 is thus transmitted to hands 31, 3'6 and 40.

the integral of the elemental forces For correcting the position of thehands, there is provided a hand setting stem 43 provided wit-h acrown-button 44 outside the case and with a transmission-wheel (orcrown-wheel) 45 within said case. That hand-setting stem is locate-dsubstantially in the plane of resonator 3. The latter is symmetricalwith respect to a plane perpendicular to the oscillation plane andpassing through the hand-setting stern, and it comprises an indentationforming a free space between the periphery of the clockwork movement 1aand the resonator 3, said free space serving to house the handsettingstem 43. Said stern can be axially shifted, so that when it is drawnout, the transmission-wheel 45 meshes with the hand-setting wheel 41through the medium of lever 46 and rocking-bar 47. The hand-settingwheel 41 in turn meshes with wheel 42, the pinion 42a of which drivesthe intermediate wheel 47 With such an arrangement of the clockworkmovement, it is possible to fix a dial 46 provided with feet in thebottom plate 1 which is provided with holes 1c for the dial feet andinner threads 1e for the fixation screws.

As can be seen, the special shape of the resonator, the arms of whichfollow the periphery of the clockwork movement through the major portionof their length,

4 leaves a large free space within which can be easily housed notonlythe gears necessary for driving the hands, but also other gears such asthose which are necessary for driving a date-disc or other indicatordevices. Again, a sufiicient space provided for locating the battery, sothat it is possible to use a circular battery having a fairly largediameter, which can be inserted between the resonator arms.

The resonator having the shape of a small omega permits the use of ahandsetting stem of a conventional type. The connection of theoscillating arms to their fixation foot promotes the dissipation of theoscillator elastic energy in a quantity of matter which is substantiallygreater than in the case of the tuning-fork. I

A second form of embodiment, shown in FIGS. 6 and 7, represents aclockwork movement similar to the above described movement, with theexception that its resonator is of slightly different shape, this shapederiving from mechanical motives which will be given hereafter.

In a resonator corresponding to the first form of embodiment, thereappear mechanical effects which have been neglected heretofore, sincethey were quite immaterial in the case of tuning-forks with rectilineara-rms.

Considering a tuning-fork, it can be seen that elemental masses dm ofthe arms of that tuning fork follow during their oscillations a pathwhich is substantially at right angles to thetuning-fork axis ofsymmetry, so that the forces dm dt I I resulting from the accelerationof these masses are Jperpendicular to said axis of symmetry. Since themasses of the two arms oscillate'in phase-opposition, the resultant ofthe forces for the two arms of the tuning-fork is nil. Now, this is notthe case with the resonator according to the present invention. In fact,in the latter, the elemental masses of one ar-m describe circular arcs,the centre of which is located in the vicinity of the fixation point ofthe resonator and, since the various radius-vectors of these elementalmasses are divergent, the path followed by the said elemental masses arealso divergent. It follows that do dm dt is most often different fromzero. 7

In the ease of a perfectly symmetrical resonator, the resultant forceexpressed by the above integral is exerted at the fixation point in thedirection of the axis of symmetry. Said point of fixation, and with itthe whole watch, are imparted an oscillating movement by that force. Theoscillating movement thus generated can become very important and, sinceit is damned down quite unevenly, not only it produces a loss of energybut it also disturbs the frequency of oscillations.

With a view to lessening the effect of that reaction and achieving agood stability of the frequency of oscillation, one has endeavored toachieve an oscillator, the arms of which are fairly light and arehowever fairly rigid. How'- ever, if it is desired to increase theaccuracy of the watch rate, it is advisable to increase the frequency ofoscillations. To this end, it is necessary if it is not desired toincreasecrease the cross-section of the oscillating mass, to furtherreduce the weight of the oscillator arms. It is then necessary tofurther decrease the thickness of the oscillating arms, which results infurther decreasing their stiffness. 7 i

It is however possible to solve the above problem by using a resonatorwith perforated arms, so that its weight is lessened and thedistribution of masses is modified, without however substantiallydecreasing its rigidity. 5

FIG. 6 shows such a resonator 53, the V shaped foot 0 which (53a) isfixed to the bottom-plate '51 by means of three screws 52. Again, theoscillating portions of that resonator have approximately the shape of asmall omega and are connected by a link 53d to the foot 53a. Saidoscillating portions are essentially constituted by two arms 53c and 53din mirror-symmetry, which follow, through the major portion of theirlength, the periphery 51a of bottom-plate 51, which also constitutes theperiphery of the clockwork movement.

Moreover, between arms 53c and 53d and bottom-plate 51 a space is leftwhich is sufiicient for allowing the arms to oscillate freely. To thetwo free extremities of arms 53c and 53d are welded, or fixed bybrazing, magnetic heads 64 and 65. According to FIG. 7, the magnetichead 64, which is in mirror-symmetry with head 65, is constituted by asoft iron member 54 of U-shaped crosssection, with lpolar pieces 55a and55b fixed to the free extremities 54a and 54b, respectively, of the softiron member 54, and having a shape adapted to that of the coil. Thematerial used for manufacturing oscillator 53 and members 54, 55a and55b, is preferably the same as that described in the first form ofembodiment.

In each of magnetic head 64 and 65 is made a cylindrical holeperpendicular to the oscillation plane. The object of said hole istwofold: in the upper portion thereof is located a cylindrical member67, friction-tight fitted in its housing and which can be rotated bymeans of a screw-driver and the masses of which .are eccentricallydistributed. Such an eccentric distribution of the masses is ensured bya recess 68 provided in the lower half of said member. The requiredfriction between cylindrical member 67 and the corresponding magnetichead is achieved by means of a diametral slit made in the face 69 ofsaid cylindrical element, which provides the latter with a certainresiliency which urges it against the wall of its housing; that slitwhich coincides with the screw slit also serves as a finger moving alonga scale 70 carried by each of the magnetic heads. That member has, overthe known precision setting members, the advantage of being fully sunkin the magnetic head.

These eccentric masses permit to achieve a precision setting of thefrequency, since, when said masses are turned, their centres of gravityand, therefore, the centre of gravity of the whole oscillating part, areshifted, so that the natural frequency of oscillation of the oscillatingmass is modified. Into the lower portion of hole 66 is introduced a pin71, fixed to the bottom plate, of a smaller diameter than that of thehole and adapted to restrict the oscillation amplitude in the plane ofoscillation, with a view to prevent the resonator from being damaged byshocks.

In order to reduce to nil the resultant force acting upon foot 53a, theoscillating portion of the resonator is imparted a suitable shape. Onecan easily see that the elemental masses forming the whole oscillatingmass, describe paths which are approximately convergent and the tangentsof which define the lines of action of the elemental forces do dm Theoscillating mass must therefore be distributed so that the vectorialintegral of the elemental forces do elmis nil. In view of the symmetryof the resonator, that condition can be reduced to day l avy designatingthe component of the velocity in the direction of the resonator axis ofsymmetry.

However the shape of the arm is essentially conditioned by the otherparts of the watch (not shown), such as the battery, the gears, theelectric circuit, the periphery of the bottom-plate and also therequired oscillation frequency and, the required rigidity of the arms;it follows that the distribution of masses cannot be achieved simply byproperly choosing the shape of the resonator.

In order to achieve the required distribution of masses, each of theresonator arms is provided with three other holes, whereby thedistribution of the oscillating masses can be modified without howeversubstantially decreasing the rigidity and the mechanical resistance ofthe resonator.

By means of the holes made in the arms, it is also possible to increasethe frequency of oscillations. The condition that the integral of theelemental forces dv dm be nil can be determined by a graph for instance;the thus obtained reduction'to zero of the forces in the direction ofthe axis of symmetry is in general incomplete and requires slightcorrections.

To this end, the resonator, alone or mounted on the bottom-plate, isplaced on a base responsive to oscillations, connected to a measuringinstrument. The symmetry of this oscillator is adjusted in known mannerby slightly stripping with a file at appropriate places the resonatorarms, whereas the integral of the elemental forces acting in the axialdirection is reduced to zero by perforating the resonator arms. It isalso possible to reduce the integral to zero by filing the arms at aplace in the vicinity of the centre of oscillation, such as 53 By filingthe arms at such a place, the centre of oscillation is shifted, with theresult that the paths of the elemental masses are modified, a suitabledisplacement permitting the reduction of the integral to zero.

When mass produced, the resonators can be so cut that they all have aresultant acting in the same direction, for instance'in the direction ofthe coil. It is thus possible, by filing the inside of the curvature53), to adjust the frequency and symmetry, and to reduce to zero theintegral of the elemental forces, by enlarging the perforations made inthe arms.

Of course, the resonator according to the present invention is notrestricted to the above-described forms of embodiment. In particular, itis possible Without going be yond the scope of the invention to modifythe number and the distribution of the perforations made in the arms.

What is claimed is:

1. An electronic watch having a hand-setting stem in the plane of theclockwork movement and an audio frequency mechanical resonator servingboth as a time-basis and as a driving member, said resonator followingthrough the major portion of its length the periphery of the clockworkmovement, the oscillating part of said resonator being an approximatelyomega-configuration with a narrow elastic neck at its central portion,said resonator comprising two arms fixed to each other and symmetricalwith respect to a plane passing through the axis of said hand-settingstem and having an indentation leaving a free space between saidresonator and the periphery of the clockwork movement, said space beingadapted to house said hand-setting stem, said hand-setting stern beinglocated at least approximately in the plane of said resonator.

2. In combination in an electronic watch with an audio frequencymechanical resonator serving both as a timebasis and as a drivingmember, said resonator having an omega shape following through the majorportion of its length the periphery of the clockwork movement, saidresonator comprising two arms fixed to each other and having anindentation at the juncture of said arms which leaves a free spacebetween said oscillator and the periphery of the clockwork movement,each of said resonator arms being provided at its extremity with a masscarrying a member, each of said members being adapted to modify thenatural frequency of said resonator, each of said members beingconstituted by a rotatable body sunk in the respective one of saidmasses, and the centre of gravity of which is eccentric.

, 3. An electronic watch with a hand-setting stern in the plane of theclockwork movement and an audio frequency mechanical resonator servingboth as a time-basis and as a driving member, said resonator followingthrough the major portion of its length the periphery of the clockworkmovement, said resonator having an omega shape comprising two arms fixedto each other and being symmetrical with respect to a plane which passesthrough the axis of said hand-setting stem and having an indentation atthe juncture of said arms leaving a free space between said oscillatorand the periphery of the clockwork movement, said space being adapted tohouse said hand-setting stem, said hand-setting stem being located atleast approximately in the plane of said resonator, each of saidresonator arms being provided at its extrer'nity with a mass carrying amember, each of said members being adapted to modify the naturalfrequency of said resonator, each of said members being constituted by arotating body sunk in the respective one of said masses, and the centreof gravity of which is eccentric.

. 4. An electronic watch with an audio frequency mechanical resonatorserving both as a time-basis and as a driving member, said resonatorhaving generally an omega shape following through the major portion ofits length the periphery of the clockwork movement, said resonatorcomprisingtwo arms fixed to each other and having an indentation at thejuncture of said arms which leaves a free space between said oscillatorand the periphery of the clockwork movement, each of said resonator armsbeing provided with at least one perforation, said perforation being sopositioned and sized that when the oscillations occur the resultant ofthe accelerations of the elemental masses of said arms is nil.

5. An electronic watch as claimed in claim 1 with a generallyomega-shaped audio frequency mechanical resonator serving both asatime-basis and as a driving member, said resonator followingthrough'themajor portion of its length the periphery of the clockwork movement,said resonator comprising two arms fixed to each other and having anindentation which leaves'a free, space between said oscillator and theperiphery of the clockwork movement, each of said resonator arms havingat its extremity a magnetic head, an opening in said head perpendicularto the plane of oscillationthereof; a rotatable member having aneccentric centre of gravity mounted in the upper part of said opening,for modifying the natural frequency of oscillation of said resonator;and in the lower part of said opening, an amplitude li-mitator toprotect said resonator from shocks.

6. A resonator for timepieces, said resonator'comprising a V-shapedfixation foot and oscillating arms, said arms being generallyomega-shaped and having a narrow elastic connecting neck connecting themto said foot, whereby said resonator is adapted to be mounted in a watchcase with said arms isolated from the watch case thereby keeping asubstantially greater part of the vibrating energy in said arms.

References Cited by the Examiner UNITED STATES PATENTS 2,433,160 12/1947Rusler 84-409 2,960,817 11/ 1960 Hetzel 58-23 3,192,701 7/1965 Tanaka eta1 58-23 3,202,848 8/1965 Bennett et al, 31025 RICHARD B. WILKINSON,Primary Examiner. G. F. BAKER, Assistant Examiner.

1. AN ELECTRONIC WATCH HAVING A HAND-SETTING STEM IN THE PLANE OF THECLOCKWORK MOVEMENT AND AN AUDIO FREQUENCY MECHANICAL RESONATOR SERVINGBOTH AS A TIME-BASIS AND AS A DRIVING MEMBER, SAID RESONATOR FOLLOWINGTHROUGH THE MAJOR PORTION OF ITS LENGTH THE PERIPHERY OF THE CLOCKWORKMOVEMENT, THE OSCILLATING PART OF SAID RESONATOR BEING AN APPROXIMATELYOMEGA-CONFIGURATION WITH A NARROW ELASTIC NECK AT ITS CENTRAL PORTION,SAID RESONATOR COMPRISING TWO ARMS FIXED TO EACH OTHER AND SYMMETRICALWITH RESPECT TO A PLANE PASSING THROUGH THE AXIS OF SAID HAND-SETTINGSTEM AND HAVING AN INDENTATION LEAVING A FREE SPACE BETWEEN SAIDRESONATOR AND THE PERIPHERY OF THE CLOCKWORK MOVEMENT, SAID SPACE BEINGADAPTED TO HOUSE SAID HAND-SETTING STEM, SAID HAND-SETTING STEM BEINGLOCATED AT LEAST APPROXIMATELY IN THE PLANE OF SAID RESONATOR.